SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bc6444d46678c07dbbbf6e7f7cd54a0cfd13834f7b972c55cabc1756d1ae607' 
  AND token = '5DzeJopfV0+jRSFQZG5DBiopucmhylVbqPIH7C+l8B4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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