SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e46c88d753d807e3ee8b9c811ac377f50f51e9d064efdef844674cbd917f9a9e' 
  AND token = '5/dw991NvE14RMGLx21fZBan78JZRSDwLhWbwhIePpE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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