SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5a3f422174f91a8b0b44e34657c7262e5e0bef9cbc1a7d34960777ff640a602' 
  AND token = 'Os5SPhLLysRiFoZyFWFniWmQlbm/YBvHdnSbQ48msvQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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