SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53c7cf8bd0f1071151538af5096b763f01124d155867d00fdcace9ffc09629db' 
  AND token = 'oHoYWol4MhN5jXPApQNVJxtZNYn3bO2KgAvsRBsQPSo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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