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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7bc9be8ee407ff0846f324c931def3eef67d542cfa4d4652e2ba8e2cb67fdb8' 
  AND token = 'r9/cd/wAHtjpwWdJ+2F9osYmn6kWMIBBC9puZp41f4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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