SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab4c651e05ca2c8a849c444661d8c9ababf32c3fd686ead628d29397400cb53c' 
  AND token = 'F1iQDuBClr5mJw6gt/wGfIy/Pwi3vmZSw1+v7B14H0o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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