SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '105659460c9c582507d13cd49676613dd882b1647d154f5febc7729f5be855de' 
  AND token = '5eko5T2gTFbFkkk6wgeLVXFV7jVGC8+0xGm+/XVkwG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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