SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '244f0b747ac356034f01eaa2693a2e28f950681ece3459a8b01546757ce22c05' 
  AND token = 'VL0ncXAXV9xB69so2N52DVRfZok295PD4KbfVypn8Bc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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