SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7ba6df61133e993284b47173be63675e093d224c1f9dd7eb361834d03d1b8f03' 
  AND token = '2K7wB3/MZL+Sl9OPv+KJst2pum7flV5IAw//33fDPuk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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