SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce0b5f82f09c04850912575b797b3bc059ddf6e4cffd81280b2b6644f587d49d' 
  AND token = '7qOsLxWGp/vnIlg+/RNLRJPPfH0w35uRNuPH3gYC+x4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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