SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4dfacca7bc846b2e4d79164fcf510acae10b6607e7ff2b7db9d44c0d37ff879' 
  AND token = '21Hmd7G1BD8AS25o8LT4mO4Eeh/V0IraUBPMv/IckRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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