SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d03e8373e298e5255520afb36e19980c3e479fa1eb738da65d6ff256277776e' 
  AND token = '+hKSW2hh5jNAQjHqVHsvd10isckhnafLvNFPjsiRG1o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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