SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93f189cad141339b7a650370d845ef6181b5d967770e7dc3f7c49d649d058397' 
  AND token = '+3LSGZFolK4Un5CoJAZQsVcgOTZ/a00ChPulR08kJ+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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