SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e48caeeeb06a87b361fd3570aa12473755ae8dc902bf661029b7ef3f1b1f801e' 
  AND token = 'LRTNGVDh+nXvfvY95l1FHN6Itx8FgCogvjSr1MQzZ94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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