SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8a09ba9217ee695634a1b54be581c2b35613982938c7e821e376edf9e6084b4' 
  AND token = 'e//dkYD42nZagkgsNSjwtynhq9vvQ5Pmw+brCSx7QZA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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