SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd35cdbe1388ec352e3a1063f11768b4219c4272742f9f4709da80d62d2f8bbb8' 
  AND token = 'lvCPwPyVX9sYvRzdPxAqC9XScbh5BEZUluLcf2QSlps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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