SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c01f62a514ce3ef6b1cf5830e2974658f5edeeb0641b52d46ded415ef53ebee3' 
  AND token = 'iEDx3c9dfJz/wa9twNzlUpfv1VaA7QAcgIhpVIgjUDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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