SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af5625d3d1f00e5baac5cfe1cb7225055d344feba7c19571f4afd869faadc891' 
  AND token = 'JALOzopclc/Me11ROulrS198qeHa0PxRatJROrGewBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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