SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bd524f05d45f74404ab2e2510d5fccb4d73c8ee744646436f09372f6534d1bf' 
  AND token = '3Se0kHTjTY7oBtt8nP2Tijjonbi9Ta0IkDRoW8KT1G0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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