SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd57a19811258c2580009c0fc2dd36097068f6fb4a58c278b0a951d0a314b910c' 
  AND token = 'exUO6tzvt7U3Ecmq9eSL5IlHXNTiTzA4ECIVir+Cr30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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