SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e04457ad16b4db5576ddc334bdd301431bb355f764895ca9f8ec5d12e2f315f' 
  AND token = 'xvr8yI2wkUHJG2SLdfa3SDgHYMV2Wzv6jMzjOVkKWPw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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