SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e655871f8161c42cc971ff82afffc246db58e9180692317b2bb10204aaf62a6' 
  AND token = 'TC9vRhefgGTfmttCa7vEZQSQ8L+KJnKPkXBCTZykP6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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