SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53d20dc3b7b94b506a96626cff9c41672eb8b67166de18082a349338b94b8c4b' 
  AND token = '3nz26ETxrBi08KyYf4ekaxB3UWccholCrjgJo7obOQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}