SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96a5547c3869c0e8841743ef44f5823597fd93687879ca48c78bf30327bdf921' 
  AND token = 'EqpgrmDtJYn/+hq27CefrpgYOcVRza2z/efHHid6YUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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