SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd02cb59d7d49f335e5297d4f8854957450ff8d49240ea739604e027cbc8a659d' 
  AND token = 'nUsuuDyluPJdIbBJCS/rfaC9v0zAzGetnIjDpdS94Vc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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