SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14fe9bb1b8c48dec3b26bd538ad39809de28f9f843abd1b31339a2c15d1bf750' 
  AND token = 'uKyUFkAPfAdJgNe03OxNWyoSkn4kGhFH1d8wpixyhFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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