SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6620c7ffe64472b8ffcbefb99ec95071fb1d4a48715ef62039e5819e0663c739' 
  AND token = 'W42tUyDFxo/dMUORJ3Ws/oY79XRmsk5YZYApduy53k4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}