SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b97d40ab423bb66d20d9ec3015f08ccff906fe5aa0044ba103791fdeeda144ef' 
  AND token = '9RMkJ0EuZLNgzCLRdM3R2/I8M7N/RqwSum0k2coIAh0=' 
  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"
    }
  }
}