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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ce44abd9f3cc6622570ce26bd5c1b9ec8a3c84b26fe00c3d9670f8a79ca35718' 
  AND token = 'Z8A62GMMaQ+WgLfy/WQfZFccuSr3oOLsMQxvJ6xF5GU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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