SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e03622523cb70ab25100fa08fa28c7c3fb0047b0aea74d95c043d4e3581c66f' 
  AND token = '6NrG91qHozm44VBqTKKp+W91Aa2EppkyhmKqeyKKMak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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