SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4c58c48af1f827038ab5fcaf71b9bc62a098116c6b66153f773d4b1355eda74' 
  AND token = 'qnThvfKqu2WprFoSlVRnG6lS/NCwRZtUM7PJElZv+tQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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