SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7476a3e9001fac7d9fedfd68b98ca94675d340e7e3573863f49169367e0b0d6c' 
  AND token = 'ri5VRtjvbY18p+wiBi9nvGypVzJ7yFwcXbCHMx5KUm0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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