SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b286d1d0f3247b0fa0797dbcab412c82d1cd5d450b35dbb7a2ca03bd4c000804' 
  AND token = 'pZMck0mRlMcOWDqNmwWFbrveQnle6yae5XIkBjSqo/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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