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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c9b6e40d4410959d19aced5e5999a83ba7077ba9facdfee7470e7a3676eca12a' 
  AND token = 'CGhi//xCe+ZXPbARsJIdZslaUj7OD1NSYmWXqCLDzyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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