SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e7643a30be784827ad3aec256e9f6128db90c690e12d86955d5e6b36e90d635' 
  AND token = 'U3cyLLD2QjEAPSHSRtALSXbdYLuqwciFijYOv/VFXIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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