SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f87c74dadbf747aaf81367f39c84ce3861cc3d5f574bd041f8899c4a403673f' 
  AND token = 'kMvsp80VNTQukrXBOMwfAcKk1/CU1hpFD3pCBE+fDdk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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