SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '510d0686a62af404a06c55d0f1a7779ed832f6864c978a1a7bf2c3818ad18bd5' 
  AND token = 'CFFj+HU9vcwUMSD35ZD+SOv9zWw/NJTtCu7m/UP3hbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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