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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f6dd995fde2c6038028da01c9d4b45dcf5d50691dbde3b5fda284a99aaa17dd1' 
  AND token = 'QUi8XHJufD0rWgLYOdQl64QrPn9+fRvFAIm0VQvOJ74=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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