SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03dd9cccaf52dbd9c55cebc795a954f434491df6acd6e385b71fef3de6158c19' 
  AND token = 'KIl5/mPFldPW4uLxzzGAVeAEJL4nHqSU6HF9Sa8SCg8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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