SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cef2e9ed69204d74251442c24fd848b9208f31b4e48eca9ae55a036f5e1f459' 
  AND token = '3+0ZgcRGV/6i38YB0QdhX7SA6Z/uL2vBQ7ymsVqxmBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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