SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8bd6484e578f6bb2a65d1b3e997a9223e832bd192af564dcefc1b36a8a86e74' 
  AND token = '2rojOYZ86K1ekDQJLZHoTuqTWRutcgSjBxMCfxCqVnY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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