SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '817c64cf8733615d6b5e4d297342c0e8b06a0a883588178f2cb144f166bb9854' 
  AND token = 'I3nbwnDcjGQsdCfw/wVLYAcxzR9vLZXMPVdnJOGKhDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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