SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f44130fcb91181a8014ef3ffbce6fe3234d223bae81aab044f88cf8beccda990' 
  AND token = 'BIa2fGp/SLsdGlXO91NIFv0QwHvBJWcp2dbv972/ymo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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