SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0cbfe409949a18f6b76e9fb46f09fde301dc458d331340af395e45d8c33dec5' 
  AND token = 'VIvfjRXpgzWCx3Mv7gyEeLSCZyjJrnHHXmoWlU9akx4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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