SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39cf3cd691fac592d7c17aedef823f66e4938bd882632c5b09dc3e41f007373e' 
  AND token = 'jUkcgSS/2Us5YyswtK1rl/2J5BxK6IGFWhVLVOQ2nHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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