SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2de08ef8d0e4aa1c60f3e20364706e23668f615cf2a0f61fc05a60df553c0f6' 
  AND token = 'DNOlSGX0ahs/JIP6SQcEzm9Oq12ox+JD90cLvBBh2Lk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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