SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abe3b584ac1b4c7560ae6b81219fcd1927359effb7490c0f631da02d0388aed6' 
  AND token = 'iHWSVKq2PkI4ogUjGhkFvWqSdvijPlQ4UFc73EK0l/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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