SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eca41ce17604bb6828ab79d3054615d360f8474758220a628d9f05978e1a5353' 
  AND token = 'ElZW1qudPLVH4FTh739Nyrn6LBh54qsJQH6EgGL4CSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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