SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a02e1d398d18423551768582af8e8208ce080c7c065fbc7473e56b2ff82be127' 
  AND token = 'QnVt24mLnVzQwMrInAKZyop/caYouTxSYxN8mp9ndqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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