SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '126626bf72dc0a241e5c618a51865edc401f5c342e92e81ade8238c077520a5b' 
  AND token = 'zMnKI7p7PBQbogmLNr9g/oXyPJgkdChDkyCNIxI0PAM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}