SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7ed1862f3081578292390bf22006fbcadd8dce97633e06d4945704cc557a31e2' 
  AND token = 'hnFeFgXUabXWF/75LDyYxCdJpVkkFJMQEYE4YcjQEMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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