SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c2ab208c3be423564de8d3e42b54b951731c418f6b6a76a756cf72efe532b520' 
  AND token = 'E3gK7lVivn1FI82X0tNKel/mZ4RHBdNwmDr61Sf56BE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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