SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1e76c97e53366489c59b90c66d1436cf57fa407da7d06f20f1a2ac1c99c60ab' 
  AND token = 'D27fvnjvbIbs/UAGL/GqVXChkRSIYGr2PAiyNBTXAPg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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