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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b5886f2bd1247020b7a6726c16e8371f4125c601a60e902b6204fe65c03d84f9' 
  AND token = '1W4T06gYJC1gGcbb0XSq4P6tgmzgFRt8RdZdevTDvvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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