SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3ee288956fe3d060810d12c992579a04ca860b4edbe1695287ea461398c84d1' 
  AND token = 'FnG/BvDZHe7vxN3cZvYc102qu5EZFPpFaD0Z5NNJdlk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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